CS8600, CS8604 warnings not emmited

[igoichuk]

dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.0.100-preview-010184
 Commit:    c57bde4593

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.13
 OS Platform: Darwin
 RID:         osx.10.13-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.0.100-preview-010184/

Host (useful for support):
  Version: 3.0.0-preview-27324-5
  Commit:  63a01b08e5

.NET Core SDKs installed:
  2.2.104 [/usr/local/share/dotnet/sdk]
  3.0.100-preview-010184 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview-19075-0444 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview-27324-5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

VSCode Version 1.31.1 (1.31.1)
C# extension version 1.18.0-beta7

Expected Behaviour: show two warnings from the build output in the code editor (and in Problems pane).

Actual Behaviour: no warnings displayed

[filipw]

This was resolved by #1404
Could you please try on VS Code extension v1.18.0-beta8 or by pulling latest omnisharp by setting "omnisharp.path": "1.32.11" or "omnisharp.path": "latest".